The first teaser of The Nun, a spin-off of The Conjuring 2 (2016) and the fifth installment in The Conjuring franchise, promises that the film will be “the darkest chapter” of them all.

Set in 1952 in Romania, long before the events of the other films in the series, the film follows the investigation of a nun’s suicide by a Catholic priest, Father Burke (Demián Bichir), a nun, Sister Irene (Taissa Farmiga), and a novice, Frenchie (Jonas Bloquet).

Taissa Farmiga is the sister of Vera Farmiga who played demonologist Lorraine Warren in The Conjuring films. Whether the characters of the Farmiga sisters are connected in The Conjuring’s universe is not yet clear.

The titular character, a ghastly nun with an ossified face and yellow eyes, who is actually a demon called Valak, was first seen in a particularly striking sequence in The Conjuring 2. The story of The Nun has been written by James Wan (director, The Conjuring) and Gary Dauberman (Annabelle, the first spin-off in the franchise), with Dauberman working on the script as well. Corin Hardy, who earlier directed the 2015 horror film The Hallow, has helmed the project. The film is scheduled for a September 7 release.